Machine tool



1946. R.IH. CLARK 2,405,686

MACHINE TOOL Filed June 11, 1945 10 Sheets-Sheet 1 INVENTOR.

F055? 7- fl C2 ARK Aug. 13, 1%46. R. H. CLARK 2A35$6 MACHINE TOOL FiledJune 11, 1945 10 Sheets-Sheet 2- IN V EN TOR. P08527- ll. Q4?! ATTORNEYSR. H. CLARK MACHINE TOOL Aug. 13, 1946.

Filed June 11; 1945 10 Sheets-Sheet 4 1946. R. H. CLARK 2,405,686

MACHINE 'I'OOL Filed June 11, 1943 1o Sheets-Sheet 5 INVENTOR. I

Lu I P03527- 62 men BY Aug. 13, 1946. LARK 2,405,686

MACHINE TOOL Filed June 11, 1943 10 sheets-Sheet 6' INVEN TOR. Passer A44 men WWZIWQM- Aug. '13, 1946. R. H. CLARK 2 ,58

MACHINE TOOL Fi led June 11, 1943 10 Sheets-Sheet 7 R. H. CLARK MACHINETOOL Aug. 13, 1946 10 SheetsSheet 18 Filed June 11', 1943 R. H. CLARKMACHINE TOOL Aug. 13, 1946.

Filed June 11, 1943 10 Sheets-Sheet 9 INVENTOR. Paaaer M 62 424 BY MWZAug. 13, 1946. R. H. CLARK 2,405,586

MACHINE TOOL Filed June 11, 1943 10 Sheets-Sheet l0 INVENTOR.

Ell

POBEETH CL 609K FIG-35 ZJWLM Arne/ve ns Patented Aug. 13, 1946 UNITEDSTATES PATENT OFFICE MACHINE TO L I Robert H. Clark; Solon, Ohio,assigncr 'to :The Warner & Swasey Company, Cleveland, Ohio, a

corporation of Ohio Application June 11, 1943, Serial N01490g468f:

12 Claims.

inventionmaybe advantageously employed inmachine tools for machiningdifferent types of work. pieces.

An object of the invention is to provide a machine'tool which is soconstructed and its operations socontrolled that it will function in animproved, rapid and efiicient manner and thus enable the work pieces tobe eccnomically produced:

Another object of the invention is to provide in a machinetool' of thetype having an electric motor for driving the spindle at va ying speedsin oppositedirections; improved means for con: trolling the speedand-direction of motor operation-.--

A further object is toprovide in a machine tool of the type having avariablespeed' spindle and a slide'provided with an indexible turret;im-- proved means for controlling'the speeds; the direction-of movementand the'starting and stoppingof the spindle and which means is actuatedin part by the indexing of the-turret and in part by the movements ofthe slide;

Another and important object is to provide in a machine tool ofthe typehaving a reversible 2 drawings illustrating-said embodiment of theinvention:

Fig. '1 is .a front elevationalview of a machine toolto which theinvention has been applied,- the machine tool being shOWn for purposesofillustration as a turret lathe whereinthe slide is manually movedandthe-turretis manually indexed.

Fig. ;2 is an end elevationalview of the-ma machine tool shown in- Fig.3.

Fig. 5 is a detail viewtakenpnline 5-5 of- Fig. 3 lookinginthe directionotthe arrows.

Fig. 6 is a fragmentary-view similar'to Fig.- 4 :but'on alargerscaleand-showsthe-construction of the machine tool partly intopplan and partly inesection.

Fig. is a front view of the portion of the machine tool shown in Fig. 6and is partly in 'eleva-- tionand partly; in section; the section beingvariable speed electric motor-for driving 'the spindle'and a slideprovided with an'indexible speeds, the direction of rotation and thestarting and stopping of the motor for each step of a work cycle andwhich means can be presetand then actuated in part by the indexing ofthe -tur-- ret and in'part by themovementsof the slide,

A still further object 'is'to providein a machine tool such as specifiedin any of the above named objects improved means for plugging the motorwhen the control circuit thereto is interrupted to slow down thecoasting of said motor and also improved means for braking themotor tostop the rotation of the spindle.

A still further object is to provide the improved means specified in'thelast object, together with means for stopping and locating thespindle ina predetermined position for purposes of loading and unloading.

Further and additional objects and advantages not specificallyreferredto above will become ap-- taken substantially 0n"1ine"l''l-0f*F'ig."6looking in the direction of the arrows.

Fig.8 is a detached View. of a portion of the mechanism-shown in Fig. 6and-is on a larger scale'twithr the-"parts-shown -.in different relationship;

Fig. 9 is a view similar to Fig. 8 but shows-the parts in diiferentrelationship.

Fig: 10 is a view similarto Figs. 8 and: 9 but I shows the parts in astill different relationship.-

Fig. 11 is 'a detached-detail sectional view ona 1 larger scale taken online I l-| l of'Fig. 6 looking in the direction of the-arrows;

Fig-12 is an end view taken from the left hand end of Fig.- 6 on alarger scaleand'with the end cover plate'sremoved.

Fig: 13 is an irregularsectional view taken substantially on line l3'|3ofFig'. 12100king in the direction of the arrows.

Fig. 14 is a detached elevational view of the spindle and the drivetherefor and includes a braking mechanism and a plugging mechanism forthe motor.

Fig. 15 is a sectional view on a larger scale than Fig. 14 and is takensubstantially on line l5-l5 of Fig. 14 looking in the direction of thearrows.

Fig. .16 is a sectional view taken substantially on line :l 5! 6 of Fig.-15 and-looking in the directiozrof the arrows chine =tool'sh'own' inFigsl and is taken looking-at Fig. 4 is -a fragmentary top plan viewortho- Fig. 17 is a detached elevational view of a part shown in sectionin Fig. 15.

Fig. 18 is an end elevational view of the motor spindle and brakemechanism and is taken looking at the right hand end of a' portion ofFig. 14.

Fig. 19 is a detached elevational view on a larger scale of the controlpanel shown in Fig. 1, with certain positions of the control leverindicated by dash lines.

Fig. 20 is a sectional view taken on line 25-29 of Fig. 19 looking inthe direction of the arrows.

Fig. 21 is a detail sectional View taken substantially on line 2I--2l ofFig. 20.

Figs. 22, 23 and 24 are detached views of a part shown in Fig. 20 andare taken, respectively, along line 2222, 23-23 and 24-24 of Fig. 20looking in the direction of the arrows.

Fig. 25 is a developed view of the upper cam disk carrying drum shown inFig. 12.

Fig. 26 is a developed view similar to Fig. 25 but illustrating one ofthe two identical lower cam disk carrying drums of Fig. 12.

Fig. 2''! is a top plan view of the most left hand cam disk shown inFig. 25, with the switch button indicated in section.

Fig. 28 is a, top plan view of the third from the left cam disk shown inFig, 25, with the switch button indicated in section.

Fig. 29 is a top plan view of the fifth from the left cam disk shown inFig. 25, with the switch button indicated in section.

Fig. 30 is a wiring diagram of the speed and reverse control circuitsfor the motor.

Fig. 31 is a wiring diagram of the electrical control circuits for themachine laid out in accordance with the standardized practice of theAmerican electrical industry.

Fig. 32 is a sectional view through a commercial form of plugging switchwhich can be operatively associated with the motor and included in thecontrol circuits.

Fig. 33 is a detached view of certain of the parts of the pluggingswitch and is taken looking from the left hand end of Fig. 32,

Fig. 34 is a detached sectional View of certain parts takensubstantially along line 34-54 of Fig. 32, and

Fig. 35 is a wiring diagram of the electrical control circuits for themachine corresponding to the control circuits disclosed in Fig. 31 butlaid out in accordance with Patent Office standards and requirements.

Referring to Fig. 1 the machine tool shown therein is a turret lathe andcomprises a bed 35 supported on spaced pedestals 36 and 31. A headstock38 is carried by one end of the bed 35 pinion meshing with a rackcarried by the slide as is well known in the art.

The turret is indexed automatically by the movement of the slide and islocked and clamped by well known mechanism for that purpose andtherefore not illustrated herein. The central stud of the indexibleturret 49 extends into the slide 45 and has fixed thereto a bevel gear59 which meshes with a. bevel gear 5! fixed to one end of a shaft 52that is parallel to the ways 43. The shaft 52 extends rearwardly withinthe slide and passes through and is fixed to a stop roll collar 53, seeFig. '7, The collar 53 abuts against one side of a bearing boss formedin the slide 45 and said collar 53 is rigidly connected to the end of 9.reduced portion of a stop roll 54 and which reduced portion rotatablyinterfits said bearing boss while the shoulder on the stop roll at theinner end of the reduced portion engages the opposite side of thebearing boss from the collar 53, wherefore the stop roll is held againstrelative endwise movement with respect to the slide 45 but can rotaterelative thereto.

The stop roll 54 rearwardly of the reduced portion thereof is in theform of a sleeve and the rear end of the stop roll is rotatablysupported in a bearing boss 55 formed in a supporting bracket attachedto the end of the slide and having a sleeve portion 55 surrounding thesleeve portion of the stop roll and an integral cam disk supporting drumhousing portion 51 for a purpose later to be explained.

The stop roll collar 53 is provided with a plurality of circularlyspaced openings concentric to the shaft 52 and aligning with threadedbores formed in the reduced portion of the stop roll. Adjustable stopscrews 53 extend through the threaded bores of the stop roll and throughthe openings in the collar 53 and can be adjusted longitudinallyrelative to the stop roll by means of wrench heads formed on the stopscrews within the sleeve portion of the stop roll. The stop screws willcorrespond in number to the different indexed positions of the turretand it will be noted that as the turret is indexed the stop roll will besimultaneously indexed through the beveled gears 59, 5! and the shaft 52to bring the stop screws successively in line with a movable stop member59.

4 member 59 abuts after it has been moved by the and rotatably supportsthe work spindle 39 and chuck 39a and which spindle is driven by areversible variable speed electric motor 49 supported by the pedestal 36and operatively connected with the spindle 39 by means of belts Hextending around a pulley on the motor shaft 42 and a pulley on the workspindle 39, see Figs. 1 and 14.

The bed 35 is provided with longitudinally extending ways 53 which areparallel to the work spindle 39 and adjustably support a base 44 onwhich base slides a turret slide 45 having thereon an indexible turret45. The base 44, in a manner well known in the art, can be moved to andclamped in adjusted position on the ways 43, while the slide 45 ismanually moved on the ways of the base by means of the turnstile 4'!fixed to a shaft 48 which carries a pinion 49, see Fig. 6, and isrotatably supported in the base with the stop screw which is inalignment therewith. The

positive stop lug 9! is provided with a recess which slidably receives apin 52 carried by the movable stop member 59, wherefore said member andthe rod 69 are held against rocking movement.

It will be seen that when the slide 55 moves forwardly toward the chuck39a carried by the work spindle 59 the movable stop member 59 will beengaged by one of the stop screws 58 when T the slide approaches itslimit of forward movement and during the remainder of the forwardmovement of the slide for non-threading operations the movable stopmember 59 will be moved into engagement with the positive stop lug 6iand the forward movement of the slide is then positively arrested. Thismovement of the movable stop member 59 compresses the coil spring 93which surrounds the rod 59 between a collar 64 fixed to the rod and apart of the base 44. The rod 60 has its right hand end, as viewed in thedrawings, slidably supported in a bore formed, in the baseiM. for apurpose later to be pointed out. The cam rod 60 is provided with. astepped recessed cam portion. for'the purpose of controlling themotor149 during threading operations, with the lowermost part of saidportion connected to the first step by an inclined camming surface 60a,while said first step isconnected to thesecnd step a' similarinclinedcamming surface 60b, seeFigs. 6, 8, 9and 10.

The base 44 is also provided with a bore which communicatesperpendicularly with the bore in which the cam rod' 60. slides and whichbore slidably supports a cam plunger 65 which has a reduced portionextending through a shouldered bushing 66 and outwardly of the base 44,said bushing serving as an abutment for one end of a coil spring 6'!which surrounds the reduced portion of'the plunger and has its oppositeend abutting the enlarged portion thereof, as clearly shown in thedrawings.

The reduced portion of the cam plunger extends outwardly of the bushing66 in the" base 44' atthe rear of the machine and'into a housing 68secured to the rear'side of the base. An arm 69 is.pivotally supportedat T0 in the housing intermediate the ends of the arm and said armcarries'a switch LS3 which is actuated by a switch button H axiallyaligned with the cam plunger 65. The switch LS3 is'located on one sideof the '3 pivot 10 for the arm 69 and said arm on the opposite side ofsaid pivot is provided in its edge with a stepped holding notch formedof two portions 12 and 13. A spring pressed plunger 14 supportedinternally of the housing 68 contacts the inneredge of the arm 69 andnormally acts to rock said arm about the pivot 10 in an anticlock wisedirection, as viewed in the drawings, and hold the arm against a partlater to be referred The housing 68 is provided with an internalbearing'boss which rockably supports the vertically extending shaft 15which has on its lower end a finger portion 16 and'on its upper end athumb lever 1T, the hub of which is provided with a pointer portion llathat cooperates with indicia indicating the two different operativepositions of the finger portion 16, namely, the lettersL and 151"representing, respectively, late and early, see Figs; 4 and 11.

The" adjustments provided for by the thumb lever 11 refer to earlyand'late threading opera tions. As will later be explained other controlmechanism functions in conjunction with the switch 163 forthreading'operations. The finger portion 15 of the shaft 15 extends intothe recess forming the stepped holding portions 12 and 13. It will beseen that when the thumb lever is in the position shown in Figs. 6 and 8the finger portion 16 is in the holding recess '!2 and the lever arm 89is substantially parallel to the cam rod." This is the E position andwillbe used when the threading operation involves the use of a solid tapor solid die. It will be noted by reference to-Fig. 6 that when thelever arm- 59' is in the position just referred to and the plunger 65extends into the deepest portion of the cam recess of the rod 60 thereduced end of the plungeris contacting the switch button I! but is not'depressing said button. It will further be noted that during athreading operation when a stop screw 58 has contacted and moved theabutment member 59 and shifted the rod (ill from the position shown inFig. 6 to the position shown in Fig. 8 theplunger has been moved by theinclined surface a to compress the spring 6'! and to depress the switchbutton H to actuate the switch LS3 carried by the arm 69 to reverse themotor 40.

It will be noted that after the parts are in the position shown in Fig.8 the movable abutment member 59 is still out of contact with thepositive stop lug 6|. The spindle will coast in its forward rotationcausing a continued forward movement of the slide due to the threadingen'' gagement between the tool and the workpiece. When the switchLSS isactuated to eifect a reversal of the motor at, the threaded tool backsoff and disengages itself from the work piece when the motor rotatesin'the reverse direction, while the operator assists the rearwardmovement of the slide during the backing oil" of the tool by manuallyturning the turnstile 41. It will be understood that the amount ofmovement of the slide due to the coasting of the spindle depends uponthe coarseness 'or fineness of the thread being cut on the work piece,since the slide will move farther in the case of a coarse thread for thesame number of coasting revolutions than it would in the case of a finethread. If the operator finds during the setup of the machine that thethread cut on the work piece is too short or too long he may adjust thestop screw 58 to cause the latter to engage the movable stop member 59earlier or later as the case may be.

In the use of collapsible taps or collapsible dies for threading a workpiece the motor 50 can be reversed at a later pointthan was thepreviously described case, since the collapsing of the tap or dieterminates the thread cutting and therefore the coasting ofthe'motordoes' not. cause any forward movement of the slide. In theinstance just referred to the operator turns the thumb lever TI to bringthe pointer into line with-the letter L, indicating late operation ofthe switch LSSand such movement of the thumb lever brings the parts intothe relationship shown in Fig. 9.

It will be seen that the positioning of the thumb lever H in the mannerstated has caused the finger T6 to move out of the holding recess '12and into the holding recess '13 of the lever arm 69, with the resultthat said arm has been rocked in a clockwise direction from the positionshown in- Fig. 8 to the position shown in Fig. 9 and which movement ofthe arm compresses the spring plunger 74 and moves the switch button Hout of contact with the extended end of the plunger 75, although theinner end of said plunger is in the deepest portion of the cam recess inthe rod Bil. Consequently when the slide is moving forwardly and thestop screw 58 contacts the movable abutment member 59 and shifts the rod69 to compress the spring 53 the plunger will travel up the inclinedsurface 65c and onto the first step and this movement of the plunger 65brings the extended end of the plunger into contact with the switchbutton H but does not depress said button. The forward movement of theslide continues and the rod 59 is further shifted with the result thatthe end of the plunger rides up the inclined surface Sill) and onto thesecond step, wherefore the extended end of the plunger depresses theswitch button H and actuates the switch LS3 as indicated in Fig. 10.This actuation of the switch LS3 effects a reversal of the motor '49. Atthe time that the switch LS3 is actuated to reverse the motor 40' thecollapsible tap or die has completed its threading operation and willcollapse in the usual manner, wherefore the threaded relationshipbetween the threaded tool and the work is terminated and consequentlyany coasting of the motor and the spindle before reversing will notresult in any further forward movement of the slide.

The switch box or housing 58 has fixed to its outer and left hand side,as viewed in Fig. 3, a switch LS5, the switch button 18 of which isdepressed momentarily at a predetermined point in the forward movementof the slide by a dog 19 fixed to the side of the slide, see Fig. 3. Theelectrical conduits from the switches LS3 and LS5 extend from the switchbox t8 through a flexible cable 80 to the cam disk supporting drumhousing portion 5'5 where said conduits are properly connected to threeswitches later to be referred to contained within the housing portion51. It will be understood that the switches LS3 and LS5 are alsosuitably connected to the motor 40 by electrical conduits located withinthe tube 3| extending from the switch box 58 to the pedestal 36 locatedbeneath the headstock. The end of the flexible cable Bil which isattached to the housing portion 51 moves with the slide 45, as indicatedby full and dash lines in Fig. 3 and said cable is guided and supportedin a V-shaped support 82 secured to a fixed part of the machine in thisinstance the pan.

The three switches referred to above as being contained in the housingportion 5?! are indicated in Fig. 12 at LS2, LS4 and LS6, the switchesLS2 and LS6 also being indicated in Fig. 13. The three switches are eachprovided, respectively, with a switch button indicated at 83, EM and 85.The switches LS2, LS4 and LS6 are actuated by the mechanism now to bedescribed.

The stop roll 54 has a gear 36 fixed to it within the housing portion5'! and said gear meshes with three gears 87, 88 and E9. The gears 81,88 and 89 are formed on similar cam disk supporting drums 9!), 9| and 92and said drums are rotatably supported within the housing 51 on shafts23 mounted in bosses formed interiorly of the housins, see Figs. 6, '7,l2 and 13. It will be observed that the switch buttons 83, 8t and 85 ofthe switches LS2, LS4 and LS6 are located adjacent to the left hand faceof the drums Sil e! and 92 as viewed in Figs. 12 and 13 and it will beseen that said buttons are in position to cooperate withinstrumentalities carried by the drums and later to be explained.

The drums 90, 9| and 92 are each provided in this instance with sixequally spaced circularly arranged recesses 94 and which recesses facetoward the switch buttons 83, 84 and 85. One of the recesses M of eachof the drums 9i! and 91 will be aligned, respectively, with the switchbuttons 83 and 84 for each indexed position of the turret 35, see Figs.12, 13 and 26, while for each such indexed position the switch button 85will be located intermediate two of the recesses 94 of the drum 92, seeFigs. 12 and 25.

The drums 90 and 9! each carry six identical cam disks 95 (see Figs. 6and 26) formed. on shouldered portions of shafts 9 5 and which portionsslidably interfit the recesses 94 of the drums while the shafts slidablypass through openings in the drums. On the outer end of each shaft 96there is formed a button 91 which is provided on its inner face with adiametrically extending V-shaped ridge 98 which is adapted to cooperatewhen in an aligned position with a complementary groove 99 formed in thedrum 90 or 5|. A coil spring I 00 surrounds each shaft 95 within therecess 94 and acts normally to urge the shoulder 8 portion and cam disk95 outwardly of the recess 94 and toward the switch button 83 or 84.

Each cam disk 95 can be held in its innermost or withdrawn positionagainst the action of the spring I00 by turning the respective button 91to position the V-shaped ridge 9% out of registry with the complementarygroove 9%, so that said ridge bears against the outer surface of theboss on the drum, see Figs. 13 and 26, and at this time such cam disk isin an inactive position with respect to its cooperating switch button.In order to place a cam disk in switch button actuating position itsbutton 9! is turned to bring the V-shaped ridge 98 into registry withthe complementary groove 99 on the cam drum, wherefore the spring Hi9forces the cam disk outwardly of the recess 94 and into position toactuate the switch button When the drum is indexed.

Referring to Fig. 26, it will be observed that four of the cam disks 95are shown therein in inactive position, while two of said disks areshown therein in switch actuating position. It will be understood thatin the arrangement shown in Fig. 25 the switch LS4 will be actuated onlyfor two indexed positions of the turret and for the other four indexedpositions said switch will not function.

It will be noted that the cam disks 95 are on their outer faces ofconical configuration, wherefore when the drum 9! is indexed the camdisks which are in switch actuating position will cam or depress theswitch button 84.

It will also be understood that When the drum 9| is again indexed tomove the cam disk 95 out of contact with the switch button 84 the latterwill be spring returned to its normal. extended position.

Although in the foregoing description relating to Fig. 26 reference hasbeen made to the cam drum 9|, it will be understood that it applies alsoto the cam drum 9i) and the cam disks 95 carried thereby, since bothdrums 9i) and 9! and their cam disks are of identical construction andthe corresponding disks of the drums are identically adjusted in thepresent illustration, although they may be individually adjusted indifferent arrangements to suit various operating conditions.

The drum 92 is provided in three of its recesses with cam disks 95, seeFig. 25, and the buttons 91 connected to these cam disks 95 are ofidentical construction with the buttons 9'! of the previously referredto cam disks 95 and said cam disks can be positioned in either aninactive or an active position by means of ridges 98 on the buttons andgrooves 99 on the outer faces of the bosses of the cam drum 92.

It will be observed by reference to Fig. 25 that when one of the camdisks 95 carried by the drum 92 is in switch actuating position and theindexing of the drum brings said cam disk into contact with the switchbutton $5 to actuate the switch LS6 the depression of the switch buttonis a momentary one and the cam disk comes to rest in a position whichallows the switch button 85 to return to its extended position. Thisarrangement is due to the fact that the switch button 85 when the drum52 is in indexed posi tion is located intermediate adjacent recesses asof the drum 92 and that the switch LS6 need only be actuated momentarilyfor a reason later to be explained.

The drum 92 in the remaining three of its recesses 94 is provided withcam disks H)! which are of different construction than are the cam disks9.5 for a purpose which will be explained. The cam disks I are formed onshouldered portions of shafts I02 similar to the shafts 95 and areprovided on their ends with buttons I03. The buttons 163 differ from thebuttons 91 in that the former areprovidedon their sidesadjacent to thedrum 9.2 with a single V-shaped radially extending ridgeIM and whichridgecan be placed in registry with either one .of two angularlydisposed .radially extending complementary .V- grooves I and I95 formed.in the outer surface of the drum 92, see Fig. 12, wherefore it will beseen that th cam .disks IOI can .be placed in either one of two extended.positions depending upon which of the grooves 105 or 106 is placed inregistry with the ridge I94. The cam disks on their outer ends consistof .a .segmentalportion IOIa of conical configuration and asegmentalportion. .IOIb .of flat configuration. jWhen a .button IE3 is positionedwith theridge [Mengaging in groove I106 then .the cam disk II'II .is inthe position .of the most vlefthand cam disk Ill-I of Pig. 25.and asshown in .the .plan viewinFig.

27 the. switch button .85 is resting .on the flatsegmental portion .I.0lb .of .the .cam .diskandis :held

depressed. This is. theposition which any one of the cam disks .I0l. may.be brought .tofor a purpose later .to be explained. When the button 103 of .a particular cam. disk .I.0.I is .turned to bring .the ridgeJBinto registry .withthe groove l05 .that particular cam diskIiH will takethe positionindicated for the middle cam disk. I01 inFig. 25. WhenathecamdiskIBI :is in the.p0sition just referred to it will be extended sothat .as the drum 92 is indexed said cam disk. IOI will momentarilydepress the switch button .85 since the latterrides up the conicalportion I9 Ia across the center of the cam disk .IOI and thendown the;.other. conical :side of the disk as indicated bydashlinessin Fig. 25and as shown .in .plan

view in :Fig. 28, it being noted that the flat portion Ibof the .disk isnow at right angles ,tothe location it had in Fig. 27 and hence saidflat .portion now will not hold theswitch. button depressed. Thepurpose. of the arrangement of the middle cam disk .I9;I.of Fig. as justreferred to will be explained hereinafter.

. The most right hand cam disk I0.I .of Fig. :25 is shownin the third.position of adjustment which can be imparted to the camdisks .IOI,namely, said cam disk is withdrawn to an inactive .position wherein itwill not .ccntactthe switchbutton 85 to depress .the same asthecarndrum.92 is indexed and at this .time the ridge: I04 of the button I03 iscontacting thefaceofthe bossof-the drum .92 and holding the cam disk ininactive position (seeFig. 29.).

As shown in Fig. 1 a control panell 01 is secured to the front side ofthe headstock .33 and said control panel is shown in Fig.119 on a.larger scale. The ccntrol'panel I01 carries. a master switch controllever I which is fixed in a lever bracket I09. The lever bracket I09 inits lower portion and adjacent to the panel I0? is providedwith a recessH0 into which extendsthe projecting end of a switch shaft II l later tobe referred to. Abearing pin H2 is carried by the bracket .I09 andextends through the shaft III and forms a pivot about which the bracketand the lever "I08 can be rocked from the ful1lineposition of Fig. 20 tothe dash line position thereof, it being noted that the lower right handportion of the bracket I09 isbeveled to permit this rockin movement andto .form a stop to limit the extent thereof. Bracket-I09 is providedwith a vertically extendated forreverse operation of the motor :10. soonas the operator releases the lever I98 the from the pin 125, see Fig.21.

ing recess'in which is slidably mounted a spring pressed plunger I I3which engages the upper side If the shaft I l I and which functions inconjunction with a pin IIA carried by the bracket and engaging theunderside of the shaft to return automatically the bracket I99 and thelever I08 when released from their outwardly swung position, i. e., thedash line position of Fig. 20, back to their normal or full lineposition. The recess in the bracket I09 engages with flat portions ofthe shaft I I I, wherefore said bracket I09 and the lever I58 can berocked about the axis of the shaft H I into any one of four differentpositions.

The bracket Hi9 above the recess H0 i provided. with a flat segmentalshaped surface adjacent the panel I01 and said surface contacts .aswitch rod I l5 which is slidably supported by the panel I0! and has atits inner or right hand end, as viewed in Fig. 20 a recessed portionhousing a coil spring I I8 which abuts against a reversing switch LSIand functions to urge the switch bracket I99 from the full line-positionof Fig. 20 :into the dash line position thereof the rod II5 moves towardthe left under the action of the spring II6 andthe switch button II'Ifollows the movement of the rod and the switch LSI is actuspring pressedplunger II3 overcomes the spring HS and will restore said lever, thebracket I09, andithe rod II-5 to the position shown in full lines inFig. 20, at which time the button III of the switch LSI is againdepressed and said switch is set for forward actuation ;of the motor.

' The switch shaft as previously stated is rockably supported in thepanel I01 and it will be noted by reference to Fig. 20that the rear endof said shaft is rockab-ly supported in a plate I-I8 carried byaplurality of parallel rods I I9 secured in and projectin rearwardly fromthe panel I01. The switch shaft 1 I I :i provided with a plurality ofaxially spaced shoulders I20, I H, 122, I23 and I 24. Two actuating pinsI25 and. IE5 extend betweenthe shoulders I20 and I2I and said pins areparallel to the shaft ;I II but radially spaced therefrom, with the pinI25 angularly spaced l'2'iextends between the shoulders I2I and I22andzsaid pin is located in a manner corresponding to the location of thepin 125, see Fig. 22. An

actuating pin I28 extends between the shoulders i 22 and I23 and saidpin is similar to the pins previously referred to except that it islocated in a different position circumferentially of the shaft andshoulders as indicatedi Fig. "23. An actuating pin I29 extends betweenthe shoulder I23 and I24 and said pin I=2 9 is similar to the previouslydescribed pins and is located circumferentially of the shaft from thepins I25 and I2'I, see Figs. 21, 22 and 24.

Four of the rods II9 are grouped in pairs above and to the left of theshaft I II, as viewed in Fig. 21, and these rods support cooperatingswitch contacts I30, I3I located soas to extend past the shaft III andbetween-the shoulders I20, I2.I, I22, I23 and I24 and the switchesformed by thecontacts I30 and I 3| are herein- An actuating pin 11 afterdesignated as switches MSI, M82, M33 and M54, see Fig. 20. Each of thecontacts I36 and IEI has a clip portion I32 which embraces the rods IIEIand holds the contact in proper position thereon.

It will also be understood that the contacts I30 and I3I are suitablyinsulated from the rods H9 and at their upper ends are provided withcontact screws II3, whereby electrical conduits can be connected to thecontacts. Each contact IIII is provided intermediate its end with anoffset portion I34 arranged to be engaged by its respective actuatingpin to close the contacts I30 and II, it being understood that when saidportion is not engaged by its respective actuating pin the resilience ofthe contacts maintain the same normally separated.

When the lever I08 is positioned at high see Fig. 19, the actuating pinI25 is in contact with the portion I34 of the switch contact I3I of theswitch MSI and the contacts I30 and I3I of said switch are closed. Atthis time the pin I25, as indicated in Fig. 21, is not in engagementwith the portion I34- of the contact arm ISI. Also at this time theactuating pin I21 is in engagement with the portion I34 of the contactarm I3I of the switch MSZ but the pins I28 and I29 are out of engagementwith the portions I34 of the contact arms I35 of the switches MS3 andM84. Consequently in the high position of the lever I08 the switches MSIand MSZ are closed for a purpose later to be explained.

When the lever I08 is moved from the full line position of Fig. 19 tothe dash line low position the shaft III is rocked and brings the pinI25 in engagement with the portion I34 of.

the contact arm I3I of the switch MSI and keep said switch closed. Thisrocking movement of the shaft III causes the actuating pin I25. to rideout of contact with the portion I34 of the contact arm I3I of the switchMSI and also causes the actuating pin I21 to ride out of contact withthe portion I34 of the contact I3I of the switch MS2 and hence thislatter switch is now open. Consequently when the lever I33 is set in lowposition the switch MSI is closed. Also the rocking of the lever fromhigh position to low position causes the pin I28 to engage the portionI34 of contact I3I of switch MS3 to close said switch. Therefore, in thelow position both switches MSI and M83 are closed. At this time theswitch M52 is open.

When the control lever is moved from low position to neutral positionthe pins I25 and I28 of switches MSI and M83 ride out of engagement withthe portions I34 of the respective contact arms I3I and said switchesare now open.

Also at this time switches M52 and MS4 are open. When the control leverI06 is moved from the neutral position to the dash line.

brake release position of Fig. 19 the switch M34 is closed by theengagement of the actuating pin I29 with the portion I34 of the contactarm I3I of said switch but all of the switches MSI, M82 and M53 areopen.

The foregoing detailed description relating to the control lever I08 maybe briefly summarized by the statement that normally the switch LSI isconditioned for forward actuation of the motor 40, but can beconditioned for reverse actuation thereof by rocking the lever I08 fromthe full line position of Fig. 20 away from the panel to the dash lineposition thereof, while the rel ase of said lever by the operatorautomatically restores it to the full line position and condi- 12 tionsthe switch LSI for forward actuation of the motor. Also the lever I08can be rocked about the axis of the shaft III to any one of fourposition to selectively close switches MSI and MS2 for the highposition; open the switch M82 and close the switches MSI and M83 for thelow position; open the switches MSI and M83 for the neutral position,the switches M82 and M84 already being opened; or close the switch M84for the brake release position of the lever, the other switches nowbeing open.

The panel I01 is provided with a start button I35 and a stop button I36for actuating the main control switches later to be referred to, itbeing understood that said buttons I35 and I3Ii need only be momentarilydepressed as they are automatically returned by spring pressure to theirextended or normal positions. The control panel I01 is also providedwith rockable switch knobs I31 and I38 for controlling a set-up or runswitch I39 and a hand or auto switch l39a similar to switch I39 andillustrated in the wiring diagram later to be described. It will benoted by reference to Fig. 19 that the arrows on the knobs I31 and I38visually indicate the different switch positions for the differentsettings of the knobs.

The braking mechanism shown in Figs. 14 and 18 for the motor shaft 42will now be described. The brake mechanism is supported on a suitablebracket within the pedestal 36. Referring to Figs. 14 and 18 it will beseen that the pulley on the motor shaft 42 for the belt II is axiallyextended and can be engaged by the brake arms I40 and I4I provided withsuitable brake pads and which arms are pivoted on the sup-portingbracket at their lower ends and embrace the extended portion of thepulley. The upper ends of the arms I40 and MI are interconnected by arod I42 which extends through aligned openings in the arms. The rod I42carries a coil spring I43 which abuts the arm I40 and an adjustable nutI44 screwed on the rod I42. The rod I42 is provided with a head I45which engages one side of the arm I II while the opposite side of saidarm is engaged by a collar I46 secured to the rod I42. A collar I41 ismounted on the rod I42 intermediate the collar I46 and the arm I40 whilethe upwardly projecting arm I48 of a bell crank lever straddles the rodI42 intermediate the collar I41 and the upper end of the arm I40. Thisbell crank lever is pivoted to the arm I40 and has its long arm I49projecting through an opening in the brake arm I as clearly shown inFig. 18. The outer or free end of the arm I49 of the bell crank lever isoperatively connected to the armature of a solenoid I50.

It will be seen that when the solenoid is not energized the spring I43normally maintains the brake arms I 40 and I4I in braking engagementwith the extended portion of the pulley, but that when the solenoid I58is energized to rock the arm I49 of the bell crank lever downwardly thenthe arm I48 of said bell crank lever forces the collar I41 and the rodI42 toward the right. This action of the arm I48 of the bell crank leverresults in the arm I4! being rocked toward the right about its pivot andat the same time the brake arm I 40 which is pivotally connected to thebell crank lever is rocked to the left about its pivot compressing thespring I43 and relieving the braking action of the arms on the extendedportion of the pulley. The manner in which the brake mechanism isapplied and re- 13 leased will be fully set forth in the description ofthe wiring diagram which will come hereinafter.

In connection with the control of the brake mechanism it is oftendesirable to stop the spindle in certain definite positions tofacilitate the operator in loading the work piece in the chuck,especially when a two-jaw chuck is employed or when the chuck is held ina side opening fixture. The mechanical portion of the brake controlmechanism for stopping the spindle in definite predetermined positionsconsists of a commutator which will now be described.

A pair of rings II of insulating material is mounted on the spindle 39with the rings in axially spaced relation and these rings are eachrovided with a segmental radially extended portion I52 for a purposewhich will soon become apparent. The rings I5I support a sleeve 1-53formed of electrically conductive material and provided with segmentalopenings into which the segmental extended portions I52 of the ringsproject with the outer surface of the extended portions flush with theouter surface of the sleeve and forming therewith a continuouscylindrical surface. A pair of spaced contacts I54 are located in spacedrelation and engage the outer surface of the sleeve I53 in line with therings I5I. The contacts I 54 are held and supported stationary in theheadstock and are electrically connected with the wiring circuit as Willlater be explained. Consequently it will be seen that as the spindlerotates the contacts ride on the outer surface of the sleeve 53 for themajor portion of each revolution of the spindle and at such time thesleeve completes the electrical circuit between the contacts. However,during a small portion of each revolution of the spindle the contactsare in engagement with the segmental extended portions I52 of the ringsiii-I and since said rings are formed of insulating material theengagement of the contacts with the portions I52 interrupts the circuit.

As has been pointed out, the brake mechanism is applied by the springI43 except when the solenoid IE-fi is energized, and hence when thecommutator just described is functioning after the motor control circuithas been interrupted and after a plugging switch, laterto ce-described,has reduced the coasting rotative speed of the motor the solenoid I50will be energized during the major portion of each coasting revolutionof the motor shaft and the brake correspondingly released, while duringthe minor portion of each such revolution the solenoid is momentarilydeenergized and the brake mechanism applied by the spring M3. In words,as the motor shaft slowly coasts the brake mechanism will be momentarilyapplied each time the segmental portions i522 engage thecontacts I5 andthen released when such engagement ceases. Consequently the coasting ofthe motor shaft will be quickly terminated, as during the coastingrevolutions of the shaft the brake mechanism is momentarily applied andthen released until the shaft stops in a definite predeterminedposition.

Suitable means is operatively associated with the motor 18 for pluggingsaid motor to quickly reduce the speed of the same after the operatingcircuit to the motor has been interrupted and before the brake becomeseffective to stop the coasting rotation of the motor and spindle.Although such plugging means may take various forms the presentillustration shows a commercial and well known form of plugging switchI55 operatively associated with the motor. Even 14 though this pluggingswitch per se forms no part of the present invention it is believedadvisable for purposes of clear illustration to describe the switchsomewhat in detail.

The operating shaft I 56 of the plugging switch is operatively connectedto the spindle of the motor 49, see Figs. 14 and 32. A rotor I51 ismounted on the operating shaft I56 and said rotor operates within analuminum cup I58 which has a slight clearance between it and the rotorand between it and the housing.

The' rotor I5! is permanently magnetized and rotates with the armatureof the motor 4t and such rotation of the rotor tends to rotatethe cupI53 in the-same direction as will be well unerstood in the art. The cupI 58 is provided with a centrally located bearing shaft I59 which isrotatably mounted in a bearing boss formed internally of the housing ofthe plugging switch I 55. The cup I58 also has fixed thereto a rod I69extending in the same direction and parallel to the shaft I59 and saidrod passes through a slot IEI formed in an internal wall in the housing.The rod I6!) is held in centralized position by means of a pair oflevers 152 pivoted at their upper ends to said internal wall of thehousing and engaging at their lower ends diametrically. opposite sidesof the rod lee (see Fig. 34). Springs I63 of predetermined tensionmaintain the levers I82 in engagement with the rod and centralize thelatter in the opening Ifii, it being understood that when the tendencyof the cup to rotate becomes greater than the tension of the springs I53then the rod will move in the opening Isl and swing one or the other ofthe levers It? about its pivot and against the spring tension. A contactbar I54 is pivoted at its upper end to internal portion of the housing,while its lower end extends through a slot in the rod The bar I64intermediate its ends is provided with a contact I 65 which normally islocated intermediate a pair of spaced fixed contacts 565 and I661 butwhich When the bar its is swung by the movement of he .rod IE!) willengage with one or the other of said fixed contacts depending on thedirection of rotation of the rotor. A solenoid lie"! is located in thehousing of the plugging'switch and has pivoted thereto a latch arm I 5%which at its free end is provided with a notched portion I69 that can beengaged by gravity with the rod It!) to hold the latter in centralposition. When the solenoid I 67 is energized the latch arm i623 islifted from the full line position of Fig. 33 to the dash line positionthereof and the latch portion I89 is released from the rod I58,whereupon the latter is free to rock under the tendency of the cup I58to rotate and .it will'be understood such rocking movement will causethe contact I65 to engage one or the other of the fixed contacts I65 andI567, depending upon the direction of rocking movement.

As will be pointed out later in describing the electrical control of themachine the latch portion I69 will be in latching position on the rodI60 so, long as, the motor All is not running. The instant that themotor to is energized and corn.- mences running the latch I59 will beliftedhy the solenoid I61 and the rod I59 will be free to move with thecup I58 against the tension of the springs I63 so as to bring thecontact i555 into engagement with one or the other of the fixed contactsIBSf or I661, depending upon the direction of rotation of the motor 40.

It may be well to point out here that the torque tending to rotate thecup I58 is proportional to the speed of the motor 40 and that as soon asthe speed of the motor diminishes to the point where the tension of thesprings I53 is not overcome the levers I62 restore the rod I60 to itscentral position and disengage the contact I65 with respect to bothfixed contacts I66) and I661.

The function of the plugging switch will be explained further indescribing the wiring diagrams for the electrical control of themachine.

In order to explain the function of the parts heretofore described, andparticularly the various switches, the operation of the machine will nowbe described for both manual and automatic operation and with referenceto the wiring diagrams of Figs. 30, 31 and 35. The description of theoperation of the machine will first be with reference to the hand ormanual operation thereof and then the setup and automatic operation ofthe machine will be described. When the rnachine is manually operatedall of the buttons in the housing til at the tail end of the ram orslide are pulled out and rotated to a position wherein their ridges areout of engagement with the slots and are contacting the bosses on thefaces of the cam drums, at which time the cam disks are in inactiveposition and will not contact the respective switch buttons. In otherwords, during the manual operation of the machine the switches LS2, LS4and LS6 are not operated, it being noted, however, that switch LS6 is anormally closed switch while switch LS4 is a double throw switch whichis normally in a high speed operative position. The switch LS2 is anormally open switch.

In addition, the switch LS3 is not actuated by the stop screws of thestop roll during manual operation.

Referring to Fig. 30, the wires Il'fi, III and H2 constitute amultiphase circuit from a source of electrical energy and this circuitincludes a main disconnecting switch I13 indicated diagrammatically inFig. 30. The wires I'M, III and H 2 lead to the three contacts of theforward switch I'M. The three wires Ilt, III and I12 also lead to thecontacts of a reversing switch I15. After the forward switch I74 isengaged then the circuit is extended by the three primary wires I'm, I2!and H2 to the three contacts of a low speed switch I'IB from which theprimary wires extend to the three terminals I'I'I, IIS and IIB(illustrated in Fig. as the inner terminals) of the motor and the latteris operating in the forward direction at low speed. Assuming that thereverse switch I'I5 is closed and the forward switch H4 is opened, thelow switch remaining closed, then the wires III) and III are reversedthrough the closing of the reverse switch I15, it being noted that thewire I'I2 remains thesame. With this condition existing the motor 40will be energized in the reverse direction, it being understood that atthis time the wire III! will be connected to the inner terminal IIIwhile the wire III will be connected to the inner terminal I78.

Assuming that the forward switch I14 is closed, the low switch H6 isopened and the simultaneously operated high speed switches I86 and ISIare closed, then the circuit to the motor by the wires I'III, III andI72 extends, respectively, to the terminals I82, I83 and Its(illustrated in Fig. 30 as the outer terminals) of the motor. Inaddition, the closing of the high speed switches I80 and ISI hasconnected the inner terminals I18, IT! and I19 in an endless circuit bythose portions of the wires I'IB, III and I'I2 leading from the highspeed switch I8! and to the three CFI . the reverse switch I15.

16 inner terminals, as will be well understood in the art.

In the high speed operation of the motor 4!] when the forward switch I'Mis opened and the reverse switch I15 is closed, the wires HE! and III tothe outer terminals I82 and I83 are reversed, whereupon the motor isenergized for high speed operation in the reverse direction.

It will be understood that the forward and reverse switches are the lowand high switches just explained and the circuits through said switchesto the motor terminals are well known in the art and therefore are onlyillustrated in the conventional diagrammatic way in Fig. 30.

Referring to Figs. 31 and 35, it is pointed out that the solenoid Fwd.controls the forward switch I'M while the solenoid Rev. controls It willalso be understood that the double solenoid High controls thesimultaneously acting high speed switches I and IBI, while the solenoidLow controls the low speed switch I'It. It will be well to note at thistime that the control circuit contains certain safety interlock normallyclosed switches between the line III) of the control circuit and thesolenoids Fwd, Rev., High and Low, just referred to.

Normally closed safety switches R and F are located in the circuits forthe solenoids Fwd. and Rev., respectively. When solenoid Fwd. isenergized switch F is opened and when solenoid Rev. is energized switchR is opened. Therefore, only one of the solenoids Fwd. and Rev. can beenergized at a time.

Normally closed safety switches L and H are located in the circuits forthe solenoids High and Low, respectively. When solenoid High isenergized switch H is opened and when solenoid Low is energized switch Lis opened. Therefore, only one of the solenoids High and Low can beenergized at a time.

Referring to Figs, 31 and 35 it will be seen that the control for themachine includes a start and stop circuit containing start and stopswitches, indicating light and a master switch MSI. The control diagramalso includes a forward and reverse circuit containing solenoids Fwd,Rev., CR4 and CR3 which actuate the motor control switches and otherswitches in the circuit as will later be referred to. In addition thereis a threading circuit containing the solenoid CRI and the indicatinglight circuit for the light 223. Also the control includes the High- Lowcircuit which contains the High and Low solenoids for actuating certainmotor control switches as well as other switches. Further, the controlfor the machine includes the positioning circuit which contains thecommutator on the spindle and the solenoid CR5. Cooperating with thispositioning circuit is the brake circuit which includes the brakesolenoid I50, as Well as certain switches actuated by the solenoids ofcertain of the other circuits. A dead spindle circuit contains thesolenoid CR2 as well as the limit switches LS6 and LS5 and the holdingswitch CR2. Finally there is the plugging circuit containing theplugging switch.

In describing the hand operation of the machine a number of assumptionswill first be stated before describing the operation in detail, It willbe assumed that the slide is in its most rearward position and that theNo. 1 face of the turret is located toward the chuck of the workspindle. It will also be assumed that the main control lever I68 is inneutral position, see Fig. 19, and that the witch knobs I31 and I38 onthe panel 17 I91 are set, respectively, in the run and hand positions.In addition, the cam disks which control the switches LS2, LS4 and LS6will be assumed to all be located in the inactive position. Furthermore,the stop screws 58 of the stop roll will be assumed to have beenadjusted properly for positively arresting the forward movement of theslide at predetermined positions for each of the operative steps of thework cycle, While the commutator on the work spindle will have beenadjusted for stopping and locating said spindle in predeterminedposition.

The operator now momentarily depresses the start button I35 to close thestarting switch in the start and stop circuit and complete the circuitthrough solenoid UV by means of the wire I85 extending between the wiresI19 and Ill and including the stop switch I36 which is normally closed.The starting switch I35 and stop switch I36 are single throwspring-returned switches and the momentary closing of the startingswitch energizes the solenoid UV and closes the normally open switch UVin the holding circuit I39 and also closes the normally open switch UVin the wire I81. The wire H35 and holding circuit I86 being energizedthe primary I88 of a transformer is energized and causes energization ofthe secondary I99 of said transformer and which secondary is connectedto the indicating light 899 on the switch panel. The operator now loadsa work piece into the chuck of the work spindle and it will be assumedthat then he moves the control lever I98 into the high speed position,When the control lever I98 is in the high speed position the switchesMS! in the start and stop circuit and the switch MSZ in the high-lowcircuit are closed. The operator by means of the turnstile moves theslide forwardly and during this forward movement the dog carried by theslide momentarily closes switch LS to complete the circuit throughsolenoid CR2 in the dead spindle circuit, it being recalled that switchLS6 is normally closed. The momentary closure of switch LS5 causesenergization of solenoid CR2 in wire I9I, effects closure of normallyopen switch CR2 in holding circuit I92 and thereafter during the manualoperation of the machine the solenoid CR2 remains energized andconsequent- 1y any further momentary actuations of switch LS5 in themovements of the slide have no efiect on the circuit through thesolenoid CR2 as now established. The energization of the solenoid CR2also closes the normally open switch CR2 in the wire I 93 of the forwardand reverse circuit.

Now the spindle commences to rotate in the 'forward direction and athigh speed.

It will be seen that the forward and reverse circuit for the control ofthe motor now includes the wires I94 and I95, the switch I39, wire I93,switch CR2, wires I 99 and I99, double throw switches LS1, CRI, solenoidFwd. and normally closed switch R. Also in the forward and reversecircuit the solenoid CR4 in wire 299 is now energized. The energizationof the solenoid Fwd. closes the forward motor switch I'M and opens thenormally closed switch F in wire 296 which revents energization of thesolenoid Rev. The energi'zation of solenoid CR4 closes normally openswitch CR4 in wire 29I of the plugging circuit, normally open switch CR4in wire 292 of the brake circuit and opens normally closed switch CR4 inwire 293 of the positioning circuit.

The high and low circuit is now completed through the wire :94, wire591, switch I39a, wire I96, switch MSZ, wire 294, double solenoids high18 and normally closed switch L. The energization of the doublesolenoids high closes the high motor control switches I89 and IBI andalso opens normally closed switch H in wire 295 which preventsenergization of solenoid low.

It will be understood that when the normally open switch CR4 in wire 292of the brake circuit was closed then the circuit through brake solenoidI59 was completed through the wire 292 and the brake released.

It will also be understood that when the normally open switch CR4 inwire 29I of the plugging circuit was closed the circuit throughplugswitch solenoid I51 was completed and said solenoid released thelatch I68 of the plugging switch and said switch became free to functionin the manner previously described.

The operator continues the forward movement of the slide by the manualrotation of the turnstile until such movement is positively arrested bythe engagement of a stop screw with the positive stop lug, after whichhe revolves the turnstile to move the slide rearwardly to clear the toolfrom the workpiece and then indexes the turret to bring No. 2 face intooperative position.

Assuming that the second step of the operative cycle requires low speedoperation of the spindle in the forward direction, the operator movesthe control lever I99 from the high osition to the low position whereinswitch MSI in thestart and stop circuit and switch M53 in the high andlow circuit are closed, it being understood that switch M82 is now open.Consequently the spindle will now be rotating in the forward directionand at low speed; it being understood that no changes take place in theforward and reverse circuit from the condition of that circuit asexplained relative to the first operative step. The high and low circuitnow is completed through solenoid low by the wire I99 extending fromswitch l39a, the wire 2I9 which includes switch M83, the wire 295 andthe normally closed switch 1-1.

It will be understood that the instant switch M82 opened and the doublehigh solenoid in wire 294 was deenergized switched H closed and alsothat the instant solenoid low became energized switch L in wire 294opened, thus preventing energization of the high solenoids. Theenergization of the low solenoid closed low motor control switch I76,while the deenerigization of the high solenoids opened high motorcontrol switches 99 and I8I.

Assuming that the second operative step is a threading operation, theoperator manually moves the slide forward with the spindle rotating atlow speed in the forward direction until the threading die engages thework piece, at which time he grasps the control lever E98 preparatory toreversing the spindle operation. As soon as the threading die hasthreaded the work piece the desired distance the operator pulls thecontrol lever outwardly and away from the panel to actuate the doublethrow switch LSI in the forward and reverse circuit to open the contactsof said switch in the wire !99 of the forward circuit and close thecontacts of said switch in the wire 2.99 of the reverse circuit.Consequently the circuit through solenoid Fwd. is interrupted andtherefore forward motor control switch I'M is opened. The deenergizationof the solenoid Fwd, allows normally closed switch F to close andtherefore the circuit is completed through solenoid Rev. which closesreverse motor switch I15 and opens the switch R, preventing energize.-tion of solenoid Fwd. The deenergization of solenoid Fwd. alsodeenergizes solenoid CR which opened switches CR4 in wire 20! of theplugging circuit and wire 292 of the brake circuit and allowed normallyclosed switch CR4 in wire 203 of the positioning circuit to close.However, simultaneously with the deenergization of solenoid CR6,solenoid CR3 in wire 28'! of the forward and reverse circuit wasenergized, wherefore normally open switches CR3 in wire 208 of theplugging circuit and in wire 2&9 of the brake circuit closed whilenormally closed switch CR3 in wire 203 of the positioning circuitopened. Therefore, the brake remains released, the positioningcommutator continues to be inactive, while the plugging switch isconditioned to function when the occ'asion occurs. The operatorcontinues the rearward movement of the slide by means of the turns-tileto assist the die in running off of the work and when the die is clearof the work no will release the control lever IE3 which willautomatically actuate the double throw switch LSI to restore forwardactuation of the motor.

Assuming that the slide has been moved sufliciently far to the rear topermit the indexing of the turret, the operator will perform thisfunction and position No. 3 face of the turret in operative relationshipto the chuck of the work spindle. The operative steps so far describedhave included forward high speed operation of the spindle, forward lowspeed operation thereof and also reverse low speed operation. The mannerin which the spindle may be operated in the reverse direction at highspeed will be obvious from the description already set forth inconnection with the diagrams of Figs. 30, 31 and 35. Therefore we mayassume that the operator has operated the machine through all of the sixsteps of a complete work cycle to the point where the slide has beenmoved rearwardly at the end of the sixth step and it is desired tounload the finished work piece and load a new work piece in the chuck.

At this time the operator moves the control lever E93 into neutralposition wherein switch MFA in the start and stop circuit is open andalso both switches M52 and MS3 in the high and low circuit are open.Therefore the forward and reverse circuit is interrupted as is also thehigh and low circuit. The motor when its control circuits are thusinterrupted will continue to coast in the forward direction, assumingthat this was the last direction of operation of the motor. At this timethe plugging switch becomes eifective to slow down the coasting rotationof the motor.

As already explained, the previous operation of the motor conditionedthe plugging switch for functioning when the occasion occurred.Therefore, the movable contact E65 of said switch has been in engagementwith the fixed contact IESSF during the forward rotation of the motor.Consequently the solenoid CR3 has been energized through the pluggingswitch and the normally open switches CR3 in the plugging circuit andthe braking circuit have continued closed while the normally closedswitch CR3 in the positioning circuit has continued open. However,during the forward operation of the motor no current could flow by wayof the plugging switch through the Rev. solenoid, inasmuch as switch Fhas been held open by solenoid Fwd. The instant that switch MS! openedsolenoid Fwd. was deenergized and switch F closed, whereupon current canflow through the wire 225, the plugging switch, wires 226 and 201 toenergize solenoid Rev. and close motor reverse switch H5 and impartreverse current to the motor while it is coasting in the forwarddirection and thus slow down such coasting rotation until thespring-tensioned arms of the plugging switch move the contact I65thereof out of engagement with the fixed contact l56F to interrupt thecircuit to the solenoids Rev. and CR3. The deenergization of solenoidCR3 opens switch CR3 in wire 208 of the plugging circuit and thusinterrupts the circuit to and deenergizes solenoid I61 of the pluggingswitch. The deenergization of solenoid I61 allows the latch of theplugging switch to drop by gravity and hold the movable contact I65 outof engagement with either of the fixed contacts lBGF or IEBR, whereforeboth wires 226 and 225 are dead. The deenergization of solenoid CR3allows normally closed switch CR3 in wire 233 of the positioning circuitto close, whereupon solenoid CR5 in said circuit is energized whenevercurrent is flowing through the positioning commutator. The energizationof solenoid CR5 closes switch CR5 in wire 2&5 of the brake circuit andcauses the brake solenoid hit to be energized and the brake heldreleased even though the deenergizatic-n of CR3 solenoid has caused theswitch CR3 in wire 209 of the brake circuit to open. Therefore thespindle will be free to rotate at the slow coasting speed to which ithas been reduced by the action of the plugging switch, except that eachtime the portions [52 of the insulating rings of the commutator engagethe contacts I54 the positioning circuit is interrupted and the solenoidCR5 deenergized, whereupon switch CR5 in the brake circuit opens,deenergizing solenoid I50 and applying the brake. This application ofthe brake is momentary so' long as the spindle is coasting as theextended portions m2 of the insulating rings of the commutator will moveout of engagement with the contacts I55 and the latter will engage thesleeve l53 of the commutator and current will be established through thepositioning circuit and the solenoid CR5 again energized to close theswitch CR5 in the brake circuit and release the brake. In other words,the positioning commutator will function during each remainingrevolution of the spindle to alternately apply and release the brake andthen stop the spindle in a predetermined position. The slowing down ofthe motor and spindle by the plugging switch will allow the motor andspindle to be brought to a rest in the predetermined position by thepositioning commutator after one or two revolutions of the spindle,depending upon the adjustment of the plugging switch.

The operator can now unload the finished work piece and reload a newWork piece in the chuck and repeat the cycle of operation alreadyexplained. In case it is not desired to locate the spindle by thepositioning commutator and to have the spindle free to be rotated byhand, the operator can move the control lever I08 from the neutralposition into brake release position to close switch MS4 in wire 25!, N2of the brake circuit and maintain the solenoid I50 energized and thebrake released to allow him to freely rotate the spindle by hand.

Set-up of machine for automatic control of motor circuits When themachine is to be set up for automatic control of the motor circuits thecontrol lever I E18 is positioned and left in either the high or lowposition so that the switch MS! in the start and stop circuit remainsclosed.

The operator turns the switch knob I31 on the panel [ill to set-upposition, whereupon the for-

